In article
<6e1bfdea0812301042x70ab57capf99ce73d364d5...@mail.gmail.com>,
"Jose Mora" <try...@gmail.com> wrote:
>[...]
> I mean, some tasks are rather boring in python when compared with php,
> for example, let's imagine we have a dictionary that contains
> dictionaries that contain the times that a key appears. We, or at
> least I, would like to write something as short as:
>
> dict[k1][k2] += 1
>
> However we will have to do a longer code (this is the smallest code I
> could come up with):
>
> dict = {}
> if not k1 in dict:
> dict[k1] = {}
> if not k2 in dict[k1]:
> dict[k1][k2] = 0
> dict[k1][k2] += 1
How about one line plus an import?
$ python2.5
Python 2.5.3c1 (release25-maint, Dec 17 2008, 21:50:37)
[GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from collections import defaultdict
>>> dic = defaultdict(lambda : defaultdict(int))
>>> dic["spam"]["eggs"] += 1
>>> dic[42][3] += 1
>>> dic[42][3] += 1
>>> dic[42][3]
2
>>> dic
defaultdict(<function <lambda> at 0x661f0>, {42: defaultdict(<type
'int'>, {3: 2}), 'spam': defaultdict(<type 'int'>, {'eggs': 1})})
--
Ned Deily,
n...@acm.org
--
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